Optimism. The simple act of expecting the best. Long dismissed as unrealistic and a bit idiotic (all the 'serious' people have been very, very gloomy), optimism is now back in a big way.

The sharing of positive stories on social media is up, after a long spell of outrage domination. Even fashion is playing its part in the move to a brighter mood: more colourful rainbow stripes and sunflower prints.

Why: Because optimists apparently live longer and are healthier than pessimists. Optimism seems to have a positive impact on the risk of dying from cancer, stroke, infection and respiratory disease. This comes from a recent study of 70,000 women conducted over eight years. It's not conclusive, but it's certainly worth reining in the negativity for a bit. Apparently, even being friends with an optimist has benefits.

Why now: Because we couldn't really have got any more pessimistic, right? Consider this a correction to the last year of apocalyptic doom and gloom; a new dawn, if you will. And because expecting the best is so much more cheering than living in fear of the worst.

How: Optimists are both born and made (with an emphasis on born) but all the latest thinking around neuroplasticity suggests that we can train ourselves to look on the bright side.

Who: Management 'experts' and self-help 'gurus', eg Tony Robbins. Winston Churchill, famously, was an optimist because "it does not seem to be much use being anything else". More recently, Alexa Chung wearing Gucci's rainbow sweater, and Dolce&Gabbana sending models down the catwalk in vivid sunflower prints.